Airbags have been known and established as improving the safety of motor vehicles. Accordingly, the inclusion of airbags on motor vehicles is now a requirement in many countries. These airbags (or airbag systems) take on a variety of different forms including steering wheel airbags, passenger airbags, dashboard airbags, side-impact airbags (often called inflatable curtain airbags), etc.
All airbag systems include an inflator or other similar device that is designed to rapidly produce/channel a large quantity of inflation gas into the airbag in the event that a sensor detects a crash condition. This influx of inflation gas into the airbag inflates and deploys the airbag from a stowed configuration. In general, this deployment of the airbag causes the airbag to become positioned at a location within the interior of the vehicle that will protect the occupant and prevent the occupant from harmful impact with the steering wheel, the dashboard, the vehicle door, and/or other portions of the vehicle interior.
One type of airbag inflator known in the art is a stored gas inflator. These inflators generally contain a sealed chamber that houses a quantity of inflation gas. Accordingly, in the event of an accident, the inflator will unseal the chamber and the quantity of inflation gas will flow out of the inflator into the airbag. Such stored gas inflators are commonly used in the industry, especially in conjunction with inflatable curtain or side-impact airbag systems.
Currently, many airbag manufacturers are making attempts to increase the size of the airbags installed in the vehicle. This is especially true for inflatable curtain airbags which are designed to be sufficiently large that they will cover the entire length of the side of the vehicle interior. However, in order to make these larger airbags, modifications to inflators must also be made in order for the airbag to be inflated within the desired timeframe. For example, in order for a large airbag to be inflated in a timely manner, the exit orifice of the inflator (i.e., the area through which the gas leaves the inflator) must be made ever larger so that the inflation gas can exit the inflator faster and fill the larger volume airbag in the requisite time. As this gas orifice of the inflator gets larger, the sealing membrane (i.e., the seal that holds the gas in the inflator prior to deployment) must also become larger and stronger in order to contain the pressurized gas in the storage chamber.
Unfortunately, the use of such stronger, larger membranes creates significant problems for airbag manufacturers. For example, it is known that as the membrane increases in strength, it becomes more difficult to rupture the membrane reliably. Accordingly, complex rupturing systems (including projectiles, pyrotechnics, and/or other membrane-puncturing devices) have been implemented in order to ensure that the membrane will be properly ruptured during deployment. Of course, the use of these complex rupturing systems increases the overall cost of the inflator and airbag system.
Further, these complex membrane rupturing systems sometimes rupture the membrane into small fragments which, if unguarded, can mix with the inflation gas and undesirably flow into the airbag. As a result, manufacturers are forced to use filters to capture the small membrane fragments and prevent such fragments from entering the airbag. Again, the use of such filters increases the overall cost and complexity of the inflator and the airbag system.
Accordingly, there is a need in the art for a new type of airbag inflator and membrane rupturing device that is inexpensive, reliable, easy to manufacture, etc. and does not allow membrane fragments to mix with inflation gas. Such a device is disclosed and taught herein.